The chemistry of oxazolines has been reviewed extensively in three major review articles: (1) Wiley et al., Chemical Reviews, Volume 44, 447 (1949); (2) Seeliger et al., Angew. Chem. International Addition, Volume 5, No. 10, 875 (1966); and (3) Frump, Chemical Reviews, 1971, Volume 71, 5483. Such review articles indicate that a wide variety of ring-opening reactions of oxazolines are known but suprisingly few reactions of hydrogen sulfide with oxazolines have ever been considered.
The reactions of certain 2-aryl-2-oxazolines with hydrogen sulfide were described, for example, by Goldberg et al., J. Chem. Soc., 1919(1948) and by Fry, J. Org. Chem. 15 438(1950). The first reaction was said to produce N-(2-hydroxyethyl)benzothioamide. The second reference utilized a different 2-aryl-2-oxazoline and obtained somewhat different results (i.e. a substituted N-(2-mercaptoethyl)benzamide).
Tomalia et al. (U.S. Pat. No. 3,670,046) taught that certain bisoxazolines react with bismercaptans or hydrogen sulfide to produce polymers.
Tomalia et al. also taught in U.S. Pat. Nos. 3,630,996; 3,723,451 and 3,746,691 that hydrogen sulfide reacts with certain 2-alkenyl-2-oxazolines to produce the corresponding bis(2-oxazolinylethyl)sulfides.